well, since you opened up the subject; what's the fastest I can overclock the 328P? I just bought the MintDuino from RS and I have a few other crystals (18.432MHz, 19.6608MHz, 25.175MHz and 28.322MHz). Has anyone tried overclocking? and what programming changes would be required?

well, since you opened up the subject; what's the fastest I can overclock the 328P? I just bought the MintDuino from RS and I have a few other crystals (18.432MHz, 19.6608MHz, 25.175MHz and 28.322MHz). Has anyone tried overclocking? and what programming changes would be required?

Well the 328p is rated to 20Mhz so only those two higher crystals would be an actual 'overclocking' situation. There have been reports in the past of people successfully overclocking so I'm pretty sure 25Mhz would not be a problem, 28Mhz who knows for sure? As far as programming changes required, there are two that come to mind off hand, one easy and one not so easy. First you would have to edit the boards.txt file to change the atmega328.build.f_cpu=16000000L value of the board you are using. Second a new bootloader would have to be recompiled and burned into the chip so that the baud rate used to upload new sketches would work with the non-standard clock speed. If however you upload sketches via a hardware ISP programmer, then you don't even need to use a bootloader on the chip.

while not an arduino, but uses an 8 bit avr just like arduino the Uzebox is rolling along at 28.6Mhz, but at some point you gotta say why seeing the XMEGA series run at 32Mhz without OC(and there are arduino cores floating out there for them) and the need for speeds faster than that you cant beat the ARM based chips.